ECG (electrocardiogram) signal is obtained from the body of a patient using electrode attached to the body surface. Due to the changes in the electrode-skin impedance caused by movement of the patient, motion artifacts are introduced to the ECG signal.
As disclosed in the publication under the title of “Motion Artifact Reduction in Electrocardiogram Using Adaptive Filter”, a portable ECG recorder which uses a triaxial accelerometer to detect the subject's movement is proposed, and the triaxial acceleration signals are used as reference signal for the adaptive filter to cancel the motion artifact.